Obama: Foiled al Qaeda Plot Not a Surprise

A foiled al Qaeda bomb plot meant to coincide with the one-year anniversary of Osama bin Laden's death did not endanger any American lives, President Obama said, adding that he was "on top of this the entire time."

"I was briefed on this in April," Obama told ABC News' Robin Roberts in an exclusive interview. "At no point were American lives in danger or American aircraft in danger."

While Obama would not comment on the specifics of the operation, he stressed in his first public comments on the case that the U.S. is "learning lessons" from the intercepted explosive device, now in FBI custody.

"I don't think it should be any surprise," Obama said of reports of a new wave of al Qaeda bomb makers determined to take down an American airliner.

"I've been very clear that, even with the death of Bin Laden, even as weakened as Al Qaeda is, if you have a bunch of extremists who are adamant about trying to kill civilians then we are going to have to maintain constant vigilance and create a whole series of layers of protection and barriers," he said.

"And, you know, fortunately, what we've seen is constant improvement on the part of our law enforcement, our military [and] our intelligence officers that allows us to be able to prevent the kind of attack that we just saw."

Obama warned against complacency, telling Roberts that the nation's security apparatus will have to "just keep on working as hard as we can to make sure that folks don't get hurt."

On Monday, the government announced it had successfully thwarted a plot by a Yemen-based al Qaeda terrorist who had planned to use a modified underwear bomb to destroy a U.S.-bound commercial airplane.